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You searched for: subject:"iterative solution"
[texts]Analysis and improvement of iteration methods for solving automatic control equations Semiannual status report, Feb. - Aug. 1966 - Moore, J. W
Approximation and matrix iteration techniques for solving automatic control equations
Keywords: APPROXIMATION; AUTOMATIC CONTROL; EIGENVALUES; ITERATION; ITERATIVE SOLUTION; MATRICES (MATHEMATICS); APPROXIMATION METHOD; AUTOMATIC CONTROL; ITERATIVE SOLUTION
Downloads: 71
[texts]Development plan for space manufacturing of high coercive strength magnets - NON
No Abstract Available
Keywords: FAILURE ANALYSIS; PROJECT MANAGEMENT; RISK; ITERATIVE SOLUTION; SYSTEMS ANALYSIS
Downloads: 62
[texts]Correlations between remotely measured soil water content and surface temperatures for the Beauce Region, France - Perry, Eileen M
No Abstract Available
Keywords: ALGORITHMS; CONJUGATE GRADIENT METHOD; CONVERGENCE; ITERATIVE SOLUTION; VARIANCE; ACCURACY; CHOLESKY FACTORIZATION; EIGENVALUES
Downloads: 56
[texts]Study of the global positioning system for maritime concepts/applications: Study of the feasibility of replacing maritime shipborne navigation systems with NAVSTAR - Winn, C. B.
A geostationary reference satellite (REFSAT) that broadcasts every four seconds updated GPS satellite coordinates was developed. This procedure reduces the complexity of the GPS receiver. The economic and performance payoffs associated with replacing maritime stripborne navigation systems with NAVSTAR was quantified and the use of NAVSTAR for measurements of ocean currents in the broad ocean areas of the world was evaluated.
Keywords: CRITERIA; INFORMATION SYSTEMS; MANAGEMENT PLANNING; SYSTEMS ANALYSIS; EDUCATION; HUMAN FACTORS ENGINEERING; ITERATIVE SOLUTION
Downloads: 61
[texts]Modeling of the EUV and X-Ray Emission Spectra Induced by the Solar Winds Ions in the Heliosphere - Kharchenko, Vasil
We have carried out investigation of the EUV and X-ray emission spectra induced in interaction between the Solar Wind (SW) and interstellar neutral gas. The spectra of most important SW ions have been computed for the charge-exchange mechanism of X-ray emission using new accurate spectroscopic data from recent laboratory measurements and theoretical calculations. Total spectra have been constructed as a sum of spectra induced in the charge-exchange collisions by individual O(exp q), C(exp q), N(...
Keywords: COMPUTATIONAL FLUID DYNAMICS; AERODYNAMICS; SENSITIVITY; ITERATIVE SOLUTION; DERIVATION; DESIGN OPTIMIZATION; ELECTRONIC EQUIPMENT
Downloads: 62
[texts]Critical Velocity in Open Capillary Channel Flows - Rosendahl, Uwe
We investigate forced liquid flows through open capillary channels with free surfaces experimentally. The experiments were performed under low gravity conditions in the Bremen Drop Tower and on board the sounding rocket TEXUS-37. Open capillary channels (vanes) are used in surface tension tanks to transport the propellant and to provide a flow path for the bubble-free liquid supply to the thrusters...
Keywords: OPTIMIZATION; LARGE SCALE INTEGRATION; ENGINEERING; SYSTEMS SIMULATION; FINITE ELEMENT METHOD; ITERATIVE SOLUTION; GALERKIN METHOD; DISCRETIZATION (MATHEMATICS)
Downloads: 69
[texts]Residual stress alleviation of aircraft metal structures reinforced with filamentary composites - Kelly, J. B.
Methods to eliminate or reduce residual stresses in aircraft metal structures reinforced by filamentary composites are discussed. Residual stress level reductions were achieved by modifying the manufacturing procedures used during adhesive bonding. The residual stress alleviation techniques involved various forms of mechanical constraint which were applied to the components during bonding. Nine methods were evaluated, covering a wide range in complexity...
Keywords: DESCENT TRAJECTORIES; ITERATIVE SOLUTION; TRAJECTORY OPTIMIZATION; ALGORITHMS; BOUNDARY VALUE PROBLEMS; GRADIENTS; MESH; OPTIMAL CONTROL; SPACING
Downloads: 113
[texts]DO MICROBES REDUCE PHOSPHATE - LIEBERT, F
IT WAS DERIVED FROM THERMO-CHEMICAL DATA THAT PHOSPHATE REDUCTION THROUGH MANNITE CAN NEVER PROVIDE THE BACTERIA WITH A GAIN IN ENERGY AND IT WAS FURTHER PROVEN THAT THIS PROCESS, WHEN IT TAKES PLACE, DOES NOT PROCEED ANALOG TO THE PROCESS OF DENITRIFICATION. IT WAS ALSO SHOWN, THAT THE RESULTS OF RUDAKOV'S ANALYSES DO NOT BY THEMSELVES CONSTITUTE PROOF OF A PHOSPHATE REDUCTION. BY MEANS OF SEVERAL DISTINCT QUALITATIVE REACTIONS REDUCTION PRODUCTS OF THE PHOSPHOROUS ACID WERE SEARCHED FOR BUT WE...
Keywords: BALLOON FLIGHT; EARTH ROTATION; POSITION ERRORS; SATELLITE OBSERVATION; ITERATIVE SOLUTION; POSITION (LOCATION)
Downloads: 66
[texts]Feasibility of detecting aircraft wake vortices using passive microwave radiometers - Harrington, Richard F
The feasibility of detecting the cold core of the wake vortex from the wingtips of an aircraft using a passive microwave radiometer was investigated. It was determined that there is a possibility that a cold core whose physical temperature drop is 10 C or greater and which has a diameter of 5 m or greater can be detected by a microwave radiometer. The radiometer would be a noise injection balanced Dicke radiometer operating at a center frequency of 60 GHz...
Keywords: CONJUGATE GRADIENT METHOD; INTEGRATED CIRCUITS; LAYOUTS; MULTIGRID METHODS; ALGEBRA; ALGORITHMS; CHIPS (ELECTRONICS); CIRCUIT DIAGRAMS; ITERATIVE SOLUTION
Downloads: 82
[texts]Connector - Electrical - Mayo, J. W.
Distribution of currents to circuits using electrical adaptor
Keywords: APPROXIMATION; ITERATIVE SOLUTION; NONLINEAR EQUATIONS; ALGORITHMS; BANACH SPACE; BOUNDARY VALUE PROBLEMS; PARTIAL DIFFERENTIAL EQUATIONS; THEOREM PROVING
Downloads: 91
[texts]Concepts for a theoretical and experimental study of lifting rotor random loads and vibrations. Phase 5B: Analysis of gust alleviation methods and rotor dynamic stability - Hohenemser, K. H.
The effects of various gust alleviation methods on the random blade response in flapping were studied analytically, assuming a rigid rotor support. The analytical model assumes rigid flapping blades with elastic root restraints. Linearized equations which are approximately valid at low lift conditions were used. Because of the interblade coupling from the feedback devices, the method of multiblade generalized coordinates was most convenient and was extended to include coning, differential coning...
Keywords: CYLINDRICAL BODIES; ELASTOHYDRODYNAMICS; LUBRICANTS; COMPRESSIBILITY; DEFORMATION; FILM THICKNESS; ITERATIVE SOLUTION; MATHEMATICAL MODELS; PRESSURE DISTRIBUTION
Downloads: 103
[texts]A knowledge-based system design/information tool - Allen, James G.
The objective of this effort was to develop a Knowledge Capture System (KCS) for the Integrated Test Facility (ITF) at the Dryden Flight Research Facility (DFRF). The DFRF is a NASA Ames Research Center (ARC) facility. This system was used to capture the design and implementation information for NASA's high angle-of-attack research vehicle (HARV), a modified F/A-18A. In particular, the KCS was used to capture specific characteristics of the design of the HARV fly-by-wire (FBW) flight control sys...
Keywords: ERROR ANALYSIS; FINITE ELEMENT METHOD; ITERATIVE SOLUTION; NONLINEAR SYSTEMS; SHELL THEORY; STRUCTURAL ANALYSIS; LOADS (FORCES); RELIABILITY
Downloads: 225
[texts]Aerodynamic sound radiation from lifting surfaces with and without leading-edge serrations - Hersh, A. S.
Aerodynamic sound radiation from lifting surfaces in smooth and turbulent flow
Keywords: DIFFERENCE EQUATIONS; ELECTRODYNAMICS; OPERATORS (MATHEMATICS); APPROXIMATION; GAS DYNAMICS; ITERATIVE SOLUTION; OPERATORS (MATHEMATICS); VARIATIONAL PRINCIPLES
Downloads: 135
[texts]ON THE POSSIBILITY OF QUANTITATIVE ASSAY OF HYDRAZINE, ITS SPLITTING PRODUCTS, AND ITS IMPURITIES - SANTACESARIA, E.
A GAS CHROMATOGRAPHY METHOD IS PROPOSED FOR PERFORMING A QUANTITATIVE ASSAY OF HYDRAZINE AND ITS USUAL SPLITTING PRODUCTS, N2, NH3 AND H2. THE METHOD IS BASED ON THE USE OF TWO SWITCHABLE GAS CHROMATOGRAPHY COLUMNS; WATER AND HYDRAZINE ARE ASSAYED ON ONE NITROGEN AND AMONIA ON THE OTHER. SINCE HYDROGEN IS GENERATED BY THE SPLITTING OF HYDRAZINE, IT IS ASSAYED BY A DIFFERENTIAL CALCULATION FROM THE KNOWN CONVERSION PATTERNS OF HYDRAZINE, AFTER HAVING SETTLED THE MATTER OF THE NITROGEN BALANCE...
Keywords: BALLOONS; DOPPLER EFFECT; EARTH ROTATION; POSITION ERRORS; SATELLITE OBSERVATION; ITERATIVE SOLUTION; POSITION (LOCATION)
Downloads: 112
[texts]Ozone Contamination in Aircraft Cabins - NON
The problem and solution to the physical ozone irritation caused by ozone concentrations in the cabin of high-altitude aircraft are presented.
Keywords: NUMERICAL ANALYSIS; REAL VARIABLES; TRANSCENDENTAL FUNCTIONS; ALGORITHMS; DIFFERENTIAL EQUATIONS; HEURISTIC METHODS; ITERATIVE SOLUTION
Downloads: 123
[texts]A study on a maximum-speed wind tunnel for re-entry investigations - Nitsch, P.
Maximum speed wind tunnel for reentry measurements
Keywords: CESIUM PLASMA; COLLISIONLESS PLASMAS; EMITTERS; ITERATIVE SOLUTION; PLASMA SHEATHS; HIGH TEMPERATURE PLASMAS; MATHEMATICAL MODELS; SAHA EQUATIONS; WORK FUNCTIONS
Downloads: 77
[texts]Supercritical blade design on stream surfaces of revolution with an inverse method - Schmidt, E.
A method to solve the inverse problem of supercritical blade-to-blade flow on stream surfaces of revolution with variable radius and variable stream surface thickness in a relative system is described. Some aspects of shockless design and of leading edge resolution in the numerical procedure are depicted. Some supercritical compressor cascades were designed and their complete flow field results were compared with computations of two different analysis methods.
Keywords: COMPUTER AIDED DESIGN; TURBOMACHINERY; CONFERENCES; DESIGN ANALYSIS; OPTIMIZATION; AERODYNAMICS; AIRCRAFT DESIGN; COMPUTATIONAL FLUID DYNAMICS; ITERATIVE SOLUTION; ROTOR BLADES (TURBOMACHINERY)
Downloads: 96
[texts]Circumstellar grain formation - Draine, B. T
Dust formation around cool giant and supergiant stars is examined in terms of grain formulation. Optical properties of small clusters, molecular physics of cluster nucleation and growth, circumstellar mass flows, and their application to alpha Ori are discussed.
Keywords: COMPUTERIZED SIMULATION; LIQUID OXYGEN; SPACE SHUTTLE MAIN ENGINE; TURBINE PUMPS; COOLANTS; GRAPHS (CHARTS); ITERATIVE SOLUTION; MECHANICAL PROPERTIES; THERMODYNAMIC PROPERTIES
Downloads: 66
[texts]Fabrication of controlled-porosity metals Patent - Turk, R. R
Production method for manufacturing porous tungsten bodies from tungsten powder particles
Keywords: DYNAMIC STRUCTURAL ANALYSIS; ITERATIVE SOLUTION; MODAL RESPONSE; RAYLEIGH-RITZ METHOD; STATIC LOADS; IBM 7094 COMPUTER; MATHEMATICAL MODELS; STIFFNESS; STRUCTURAL STABILITY
Downloads: 77
[texts]The problem of glider takeoff using a tow winch - Jensen, A.
Glider flight path at takeoff using tow winch
Keywords: NONEQUILIBRIUM FLOW; SLENDER BODIES; SUPERSONIC FLOW; TWO DIMENSIONAL BODIES; WAVE DRAG; CONTOURS; FREE FLOW; ITERATIVE SOLUTION; OPTIMIZATION
Downloads: 295
[texts]Computations and turbulent flow modeling in support of helicopter rotor technology - Rose, W. C
The angle of attack (AOA) tandem cavity wind tunnel experiment was prepared. Actual wind tunnel testing started shortly after the beginning of 1985. A multi-probe aerodynamic rake was designed and installed for use in surveying the shear layers present over the open cavity on the Kuiper Airborne Observatory (KAO). The nature of the behavior of the thermal environment within the KAO cavity at operational altitudes was determined...
Keywords: ALGORITHMS; ELLIPTIC DIFFERENTIAL EQUATIONS; ELLIPTIC FUNCTIONS; ITERATIVE SOLUTION; PARTIAL DIFFERENTIAL EQUATIONS; ANALYSIS (MATHEMATICS); CONVERGENCE; RELAXATION METHOD (MATHEMATICS)
Downloads: 70
[texts]Benefits from synergies and advanced technologies for an advanced-technology space station - Garrett, L. Bernard
A configuration for a second-generation advanced technology space station has been defined in a series of NASA-sponsored studies. Definitions of subsystems specifically addressed opportunities for beneficial synergistic interactions and those potential synergies and their benefits are identified. One of the more significant synergistic benefits involves the multi-function utilization of water within a large system that generates artificial gravity by rotation...
Keywords: COUPLING; GEOIDS; NONLINEARITY; OPTIMIZATION; PARAMETERIZATION; EARTH CORE; EARTH MANTLE; GEOMAGNETISM; GEOPHYSICS; INVERSIONS; ITERATIVE SOLUTION; SEISMOLOGY; EARTH ROTATION
Downloads: 118
[texts]A Numerical Model of Unsteady, Subsonic Aeroelastic Behavior - Strganac, Thomas W
A method for predicting unsteady, subsonic aeroelastic responses was developed. The technique accounts for aerodynamic nonlinearities associated with angles of attack, vortex-dominated flow, static deformations, and unsteady behavior. The fluid and the wing together are treated as a single dynamical system, and the equations of motion for the structure and flow field are integrated simultaneously and interactively in the time domain...
Keywords: COMPRESSIBLE FLOW; COMPUTATIONAL FLUID DYNAMICS; DELTA WINGS; INTEGRAL EQUATIONS; VORTEX SHEETS; ITERATIVE SOLUTION; NUMERICAL ANALYSIS; TRANSONIC FLOW; VELOCITY DISTRIBUTION
Downloads: 190
[texts]Optimal Signal Processing of Frequency-Stepped CW Radar Data - Ybarra, Gary A.
An optimal signal processing algorithm is derived for estimating the time delay and amplitude of each scatterer reflection using a frequency-stepped CW system. The channel is assumed to be composed of abrupt changes in the reflection coefficient profile. The optimization technique is intended to maximize the target range resolution achievable from any set of frequency-stepped CW radar measurements made in such an environment...
Keywords: CASCADE FLOW; STEADY FLOW; ITERATIVE SOLUTION; MATRICES (MATHEMATICS); SENSITIVITY; UNSTEADY FLOW; ISOPARAMETRIC FINITE ELEMENTS; AIRFOIL PROFILES; UNSTEADY AERODYNAMICS; NEWTON METHODS; LINEAR EQUATIONS; FLOW DISTRIBUTION; AEROELASTICITY
Downloads: 84
[texts]Interactive Office user's manual - Montgomery, Edward E.
Given here is a user's manual for Interactive Office (IO), an executive office tool for organization and planning, written specifically for Macintosh. IO is a paperless management tool to automate a related group of individuals into one productive system.
Keywords: BOUNDARY CONDITIONS; OCEAN MODELS; PARALLEL PROCESSING (COMPUTERS); SELECTION; COMPUTATIONAL FLUID DYNAMICS; CONFERENCES; DECOMPOSITION; HETEROGENEITY; COMPRESSIBLE FLOW; COMPUTATIONAL GRIDS; FINITE DIFFERENCE THEORY; ITERATIVE SOLUTION
Downloads: 62
[texts]Spectroscopy and multivariate analyses applications related to solid rocket nozzle bondline - Arendale, W. F.
Chemical composition and molecular orientation define the properties of materials. Information related to chemical composition and molecular configuration is obtained by various forms of spectroscopy. Software algorithms developed for multivariate analyses, expert systems, and Artificial Intelligence (AI) are used to conduct repetitive operations. The techniques are believed to be of particular significance toward achieving TQM objectives...
Keywords: COMPUTER AIDED TOMOGRAPHY; PREDICTIONS; VAPORS; CONSTITUTIVE EQUATIONS; ELECTRICAL IMPEDANCE; IMAGING TECHNIQUES; LIQUID-GAS MIXTURES; TWO FLUID MODELS; TWO PHASE FLOW; ITERATIVE SOLUTION; NUMERICAL ANALYSIS
Downloads: 65
[texts]REPORT OF THE WIND POWER COMMITTEE - NON
WIND-GENERATED ELECTRICITY WAS STUDIED AT AN EXPERIMENTAL MILL AND AT WIND MEASURING STATIONS WHICH CONSISTED OF A MEASURING CYLINDER MOUNTED ON A STEEL MAST AT ELEVATIONS OF 25 AND 50 M. THE MILL IS EVALUATED IN TERMS OF ITS COST AND PERFORMANCE AND IS COMPARED TO OTHER EXPERIMENTAL MILLS IN THESE TERMS. A SYSTEM OF ECONOMIC MODELS IS PRESENTED WHICH COMPARES THE COSTS FOR WIND- AND STEAM-GENERATED ELECTRICITY, WITH THE CONCLUSION THAT A WIND POWER PLANT SUCH AS THE ONE STUDIED IS UNABLE TO COM...
Keywords: COMPUTER PROGRAMMING; ITERATIVE SOLUTION; POROSITY; HEAT PIPES; WICKS; COMPUTER AIDED DESIGN; DIFFERENTIAL EQUATIONS; FLUID MECHANICS; GRAVITATIONAL FIELDS; HEAT TRANSFER; INPUT/OUTPUT ROUTINES
Downloads: 119
[texts]Packaging printed circuit boards: A production application of interactive graphics - Perrill, W. A
The structure and use of an Interactive Graphics Packaging Program (IGPP), conceived to apply computer graphics to the design of packaging electronic circuits onto printed circuit boards (PCB), were described. The intent was to combine the data storage and manipulative power of the computer with the imaginative, intuitive power of a human designer. The hardware includes a CDC 6400 computer and two CDC 777 terminals with CRT screens, light pens, and keyboards...
Keywords: AIRCRAFT DESIGN; TIME SHARING; WINGS; AIRCRAFT STRUCTURES; COMPUTER GRAPHICS; INTERACTIONS; MAN MACHINE SYSTEMS; SIZE DETERMINATION; COMPUTER PROGRAMS; ITERATIVE SOLUTION; REMOTE CONSOLES
Downloads: 75
[texts]Production of Lunar Concrete Using Molten Sulfur - Omar, Husam A
The United States has made a commitment to go back to the moon to stay in the early part of the next century. In order to achieve this objective it became evident to NASA that a Lunar Outpost will be needed to house scientists and astronauts who will be living on the moon for extended periods of time. A study has been undertaken by the authors and supported by NASA to study the feasibility of using lunar regolith with different binders such as molten sulfur, epoxy or hydraulic cement as a constr...
Keywords: AIR TRAFFIC CONTROL; ALTITUDE; AIRSPEED; AIR TRANSPORTATION; MODELS; AIRLINE OPERATIONS; FLIGHT OPTIMIZATION; WORKSTATIONS; FREE FLIGHT; FLIGHT PLANS; ITERATIVE SOLUTION; COMPUTER GRAPHICS; MANAGEMENT SYSTEMS; DATA BASES; TRAJECTORIES; DYNAMIC PROGRAMMING
Downloads: 171
[texts]Development of an alkaline fuel cell subsystem - NON
A two task program was initiated to develop advanced fuel cell components which could be assembled into an alkaline power section for the Space Station Prototype (SSP) fuel cell subsystem. The first task was to establish a preliminary SSP power section design to be representative of the 200 cell Space Station power section. The second task was to conduct tooling and fabrication trials and fabrication of selected cell stack components...
Keywords: INTERPROCESSOR COMMUNICATION; ITERATIVE SOLUTION; PARTIAL DIFFERENTIAL EQUATIONS; MEMORY (COMPUTERS); MESSAGE PROCESSING; MULTIPROCESSING (COMPUTERS); PARALLEL PROCESSING (COMPUTERS); TIME SHARING; ALGORITHMS; ARCHITECTURE (COMPUTERS); DATA STRUCTURES
Downloads: 115
[texts]Computational Aspects of Heat Transfer in Structures - NON
Techniques for the computation of heat transfer and associated phenomena in complex structures are examined with an emphasis on reentry flight vehicle structures. Analysis methods, computer programs, thermal analysis of large space structures and high speed vehicles, and the impact of computer systems are addressed.
Keywords: AIRCRAFT CONTROL; ITERATIVE SOLUTION; VIDEO EQUIPMENT; AIRCRAFT DESIGN; COCKPITS; DESIGN ANALYSIS; MILITARY HELICOPTERS; AIRCRAFT INSTRUMENTS; AIRCRAFT SURVIVABILITY; EQUIPMENT SPECIFICATIONS; FEASIBILITY ANALYSIS
Downloads: 548
[texts]1996 Coolant Flow Management Workshop - NON
The following compilation of documents includes a list of the 66 attendees, a copy of the viewgraphs presented, and a summary of the discussions held after each session at the 1996 Coolant Flow Management Workshop held at the Ohio Aerospace Institute, adjacent to the NASA Lewis Research Center, Cleveland, Ohio on December 12-13, 1996. The workshop was organized by H. Joseph Gladden and Steven A. Hippensteele of NASA Lewis Research Center...
Keywords: MULTIDISCIPLINARY DESIGN OPTIMIZATION; LAGRANGE MULTIPLIERS; STRUCTURAL WEIGHT; ALGORITHMS; CONSTRAINTS; MATHEMATICAL PROGRAMMING; NEWTON METHODS; DESIGN ANALYSIS; STRUCTURAL DESIGN; CONVERGENCE; ITERATIVE SOLUTION; NONLINEAR PROGRAMMING; STRUCTURAL ANALYSIS
Downloads: 176
[texts]Need for expanded environmental measurement capabilities in geosynchronous Earth orbit - Mercanti, Enrico P
The proliferation of environmental satellites in low altitude earth orbit (LEO) has demonstrated the usefulness of earth remote sensing from space. As use of the technology grows, the limitations of LEO missions become more apparent. Many inadequacies can be met by remote sensing from geosynchronous earth orbits (GEO) that can provide high temporal resolution, consistent viewing of specific earth targets, long sensing dwell times with varying sun angles, stereoscopic coverage, and correlative me...
Keywords: COMPRESSOR BLADES; GEOMETRY; SENSITIVITY; SHAPES; SHOCK WAVES; EULER EQUATIONS OF MOTION; FREE FLOW; ITERATIVE SOLUTION; MACH NUMBER; TRANSONIC FLOW; TURBINE BLADES; CONVERGENCE; FLOW DISTRIBUTION
Downloads: 87
[texts]Capturing energy from the wind - Schefter, J. L
The history of windpower is reviewed. Wind turbine technology is discussed. Examples of small and large turbines are provided. Electric power generation is considered. Numerous illustrations are included.
Keywords: ALGORITHMS; IRRADIATION; NONLINEAR EQUATIONS; REACTION KINETICS; STEADY STATE; WATER; BOUNDARY VALUE PROBLEMS; DIFFERENTIAL EQUATIONS; ITERATIVE SOLUTION; PERTURBATION; CHEMICAL REACTIONS; COMPUTATION; CONVERGENCE; DETERMINANTS
Downloads: 714
[texts]An Experimental Investigation To Determine Interaction Between Rotating Bodies - Grugel, R. N.
A brass (copperzinc) wheel, with a 4-in diameter and 1.4 in thick, was used for this investigation. Ceramic ball bearings were used to safely spin the wheel up to 40,000 rpm. The wheel was also electrically insulated from the rest of the armature. For spinning, an air turbine was used. The rotational velocity was measured by two methods: (1) A simple strobe light and (2) a photodiode that detected laser beam pulses as they passed through a slot in the rotating shaft...
Keywords: FLOW DISTRIBUTION; TIME MARCHING; MACH NUMBER; UNSTEADY FLOW; GROUND EFFECT (AERODYNAMICS); ITERATIVE SOLUTION; CYLINDRICAL BODIES; CROSS FLOW; ACCURACY; LOW REYNOLDS NUMBER; STROUHAL NUMBER
Downloads: 98
[texts]Design definition study of a Lighter-Than-Air (LTA) High Altitude Powered Platform (HAPP). Volume 2: Report on phase 1 - Stefan, Kar
No Abstract Available
Keywords: BOUNDARY VALUE PROBLEMS; MATRIX THEORY; GALERKIN METHOD; PARABOLIC DIFFERENTIAL EQUATIONS; RUNGE-KUTTA METHOD; TIME DEPENDENCE; ALGORITHMS; APPROXIMATION; DISCRETE FUNCTIONS; ITERATIVE SOLUTION
Downloads: 160
[texts]Comparing barrier algorithms - Arenstorf, Norbert S.
A barrier is a method for synchronizing a large number of concurrent computer processes. After considering some basic synchronization mechanisms, a collection of barrier algorithms with either linear or logarithmic depth are presented. A graphical model is described that profiles the execution of the barriers and other parallel programming constructs. This model shows how the interaction between the barrier algorithms and the work that they synchronize can impact their performance...
Keywords: ACOUSTICS; EULER EQUATIONS OF MOTION; FINITE DIFFERENCE THEORY; ITERATIVE SOLUTION; SHOCK WAVES; AERODYNAMIC CHARACTERISTICS; APPLICATIONS PROGRAMS (COMPUTERS); MATHEMATICAL MODELS; PERFORMANCE PREDICTION; SUPERSONIC FLOW; TURBOPROP AIRCRAFT; BOUNDARY CONDITIONS; BOUNDARY VALUE PROBLEMS
Downloads: 59
[texts]Non-Linear Cosmological Power Spectra in Real and Redshift Space - Taylor, A. N.
We present an expression for the non-linear evolution of the cosmological power spectrum based on Lagrangian trajectories. This is simplified using the Zel'dovich approximation to trace particle displacements, assuming Gaussian initial conditions. The model is found to exhibit the transfer of power from large to small scales expected in self-gravitating fields. Some exact solutions are found for power-law initial spectra...
Keywords: LAMINAR FLOW; LEADING EDGES; TRAILING EDGES; GLIDERS; TRANSPORT AIRCRAFT; SUBSONIC SPEED; COMMUTER AIRCRAFT; BOUNDARY LAYER TRANSITION; PITCHING MOMENTS; AIRFOILS; LAMINAR BOUNDARY LAYER; PRESSURE DISTRIBUTION; ITERATIVE SOLUTION; DESIGN ANALYSIS; LIFT; TURBULENT BOUNDARY LAYER; STABILITY
Downloads: 55
[texts]Uniformly high order accurate essentially non-oscillatory schemes 3 - Harten, A.
In this paper (a third in a series) the construction and the analysis of essentially non-oscillatory shock capturing methods for the approximation of hyperbolic conservation laws are presented. Also presented is a hierarchy of high order accurate schemes which generalizes Godunov's scheme and its second order accurate MUSCL extension to arbitrary order of accuracy. The design involves an essentially non-oscillatory piecewise polynomial reconstruction of the solution from its cell averages, time ...
Keywords: AIRFOILS; SWEPT WINGS; VISCOUS FLOW; CAUCHY INTEGRAL FORMULA; ITERATIVE SOLUTION; KINETIC ENERGY; PERTURBATION; TURBULENCE; BUBBLES; COMPUTER PROGRAMS; INFINITE SPAN WINGS; INTERACTIONAL AERODYNAMICS; INVISCID FLOW; LEADING EDGES; SEPARATED FLOW; STATISTICAL ANALYSIS
Downloads: 135
[texts]Emplacement of Xenolith Nodules in the Kaupulehu Lava Flow, Hualalai Volcano, Hawaii - Guest, J. E.
The basaltic Kaupulehu 1800-1801 lava flow of Hualalai Volcano, Hawaii contains abundant ultramafic xenoliths. Many of these xenoliths occur as bedded layers of semi-rounded nodules, each thinly coated with a veneer (typically 1 mm thick) of lava. The nodule beds are analogous to cobble deposits of fluvial sedimentary systems. Although several mechanisms have been proposed for the formation of the nodule beds, it was found that, at more than one locality, the nodule beds are overbank levee depos...
Keywords: FINITE DIFFERENCE THEORY; NACELLES; WAVE EQUATIONS; HARMONIC EXCITATION; HYPERBOLIC DIFFERENTIAL EQUATIONS; TIME MARCHING; SOUND FIELDS; BOUNDARY CONDITIONS; SOUND PROPAGATION; AIRCRAFT ENGINES; AEROACOUSTICS; REAL TIME OPERATION; ENGINE INLETS; DUCTED FLOW; ITERATIVE SOLUTION; TIME DEPENDENCE
Downloads: 84
[texts]Temperature-Dependent Rate Constants and Substituent Effects for the Reactions of Hydroxyl Radicals With Three Partially Fluorinated Ethers - Hsu, K.-J.
Rate constants and temperature dependencies for the reactions of OH with CF3OCH3 (HFOC-143a), CF2HOCF2H (HFOC-134), and CF3OCF2H (HFOC-125) were studied using a relative rate technique in the temperature range 298-393 K. The following absolute rate constants were derived: HFOC-143a, 1.9E-12 exp(-1555/T); HFOC-134, 1.9E-12 exp(-2006/T); HFOC-125, 4.7E-13 exp(-2095/T). Units are cm(exp 3)molecule(exp -1) s(exp -1)...
Keywords: MULTIPROCESSING (COMPUTERS); PARTIAL DIFFERENTIAL EQUATIONS; NONLINEAR EQUATIONS; TAYLOR SERIES; ALGORITHMS; COMPUTER SYSTEMS PERFORMANCE; PARALLEL PROCESSING (COMPUTERS); ARCHITECTURE (COMPUTERS); LINEAR EQUATIONS; CRAY COMPUTERS; DISTRIBUTED PROCESSING; ITERATIVE SOLUTION; MEMORY (COMPUTERS); DIRICHLET PROBLEM
Downloads: 82
[texts]Silicon device performance measurements to support temperature range enhancement - Johnson, R. Wayne
The results of the NPN bipolar transistor (BJT) (2N6023) breakdown voltage measurements were analyzed. Switching measurements were made on the NPN BJT, the insulated gate bipolar transistor (IGBT) (TA9796) and the N-channel metal oxide semiconductor field effect transistor (MOSFET) (RFH75N05E). Efforts were also made to build a H-bridge inverter. Also discussed are the plans that have been made to do life testing on the devices, to build an inductive switching test circuit and to build a dc/dc s...
Keywords: AIRCRAFT CONFIGURATIONS; COMPUTER AIDED DESIGN; ITERATIVE SOLUTION; PERSONAL COMPUTERS; SUBSONIC FLOW; TRANSPIRATION; AIRCRAFT DESIGN; BOUNDARY CONDITIONS; DIRICHLET PROBLEM; FLOW EQUATIONS; OPTIMIZATION; PANEL METHOD (FLUID DYNAMICS); PRESSURE DISTRIBUTION; COMPRESSIBLE FLOW
Downloads: 102
[texts]Quantum State Engineering Via Coherent-State Superpositions - Janszky, Jozsef
The quantum interference between the two parts of the optical Schrodinger-cat state makes possible to construct a wide class of quantum states via discrete superpositions of coherent states. Even a small number of coherent states can approximate the given quantum states at a high accuracy when the distance between the coherent states is optimized, e. g. nearly perfect Fock state can be constructed by discrete superpositions of n 1 coherent states lying in the vicinity of the vacuum state.
Keywords: COMPUTATIONAL FLUID DYNAMICS; LAMINAR FLOW; ITERATIVE SOLUTION; TRANSONIC FLOW; THREE DIMENSIONAL MODELS; TWO DIMENSIONAL MODELS; EULER EQUATIONS OF MOTION; NACELLES; FUSELAGES; WIND TUNNEL TESTS; TRANSONIC WIND TUNNELS; BODY-WING CONFIGURATIONS; WAVE DRAG; MACH NUMBER; ANGLE OF ATTACK; AIRFOILS; COMPUTER AIDED DESIGN; AERODYNAMICS; WING NACELLE CONFIGURATIONS; AIRCRAFT DESIGN; COMPUTATIONAL GRIDS; PRESSURE DISTRIBUTION; FINITE ELEMENT METHOD; FLOW DISTRIBUTION; SWEPT WINGS
Downloads: 81
[texts]Measurement of Atomic Oxygen in Diffuse Aurora and Ion Density in the E-Region - Sharp, William E
An ion mass spectrometer (IMS) was refurbished, calibrated and supplied to the University of Colorado payload (Dr. Charles Barth, P.I.) which was launched from White Sands in September of 1993 as NASA 33.062. The nose cone failed to deploy and their were problems with the ACS so the mission was declared a failure. However, the door covering the IMS deployed and the instrument obtained data. The launch occurred shortly after a payload carrying solar x-ray detectors was launched...
Keywords: FLOW MEASUREMENT; HYDROSTATICS; FLUID INJECTION; HYDRODYNAMIC EQUATIONS; TURBULENT FLOW; CRYOGENIC FLUIDS; BOUNDARY CONDITIONS; FILM THICKNESS; PERTURBATION THEORY; FORTRAN; ITERATIVE SOLUTION; FLOW VISUALIZATION; HYDRODYNAMIC COEFFICIENTS; FLOW COEFFICIENTS; TURBINE PUMPS; TURBULENT HEAT TRANSFER; COMPUTATIONAL FLUID DYNAMICS; THRUST BEARINGS; COMPUTER PROGRAMS; MATHEMATICAL MODELS; COMPUTERIZED SIMULATION; JOURNAL BEARINGS; PERFORMANCE PREDICTION; STATIC LOADS
Downloads: 60
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